This structure is a very modern steel girder bridge. It represents a transition for the bridges over the great river. When heading north, this is the first of the shorter and lower bridges over the river. Traveling south, this will be the last bridge before you start getting to bridges that are major civil engineering projects. Traveling north, you often find bridges over the Mississippi River in rural areas where the roads naturally meet the river. Going south, the bridges tend to be part of major metro areas that can generate the traffic needed to justify a major river bridge.
The bridge itself is the typical 1970s and 1980s economical style steel girder with concrete deck and concrete piers. It should last 100 years or more with only routine painting and inspections.
The previous bridges in this location did not last that long. According to Mary Costello (Climbing The Mississippi River Bridge By Bridge, Volume 2), the first crossing here was a ferry service. A 3 span steel truss bridge was built in 1900. It was destroyed by ice in the spring of 1906. A new metal truss bridge was built in 1907. Due to being very narrow and lightly constructed, the 1907 bridge was more or less obsolete the day it opened. It did, however, survive for 70 years.
The photo above is the north face of the bridge looking towards the west. The photo below is a view looking west down the length of the traffic deck.
